Kevolving musical scale



i. UNITED STATES PATENT OFFICE.

SAML. D. TILLMAN, OF SENECA FALLS, NE\V YORK.

REVOLV'ING MUSICAL SCALE.

Specification of Letters Patent No. 10,217, dated November 8, 1853.

To LZZ whom z'zf may concern:

Be it known that I, SAMUEL D. TILLMAN, of Seneca Falls, Seneca county,and State of New York, have made a new and useful Instrument forMeasuring and Illustrating Musical Intervals, and that the following isa full, clear, and exact description thereof, reference being had to theaccompanying drawing, illustrating the same.

The nature of my invention consists in an improved method of measuringand illustrating musical intervals, and all relations between the fixedchromatic scale and the diatonic scale of any given key. This I effectby the combination of two or more circular disks or rings of metal, woodor pasteboard having arms leading to a common center.

Figure l represents a front view of the instrument; the outer row ofletters seen are on the lower disk, (intended to be staticnary,) andaround the center of which revolve a graduated ring, and 'also anotherdisk, either one of which may be used in connection with the lower disk;both are fixed to the lower disk by means of the same female screw. Inillustrating the musical intervals used in the piano, and all otherinstruments having l2 keys within the octave, the upper and lower disksonly need be used.

In practice the piano is tuned more perfect on some keys than on others,as it is impossible to have all correct with only twelve keys in theoctave; but as each of these twelve keys are in fact often used as thetonic or key-note, it follows that they must in theory all bear the samerelation to each other; each in turn must represent a tone, a semitone,stand for the sharp of the note below, and the flat of the note aboveit; and therefore in represent-ing these mu* sical intervals bydistances or degrees on a circle, I divide the circle on the outer diskinto twelve equal parts, numbered like acomnion clock face, each ofwhich represents the interval of a semitone, and two of them unitedwould mark a tone. In the diatonic scale which contains the naturalnotes of the octave, the intervals commencing at C as the tonic orkey-note, are by the letters C, D, E, F, G, A, B, on the lower disk.Here we find five tones, or intervals of the same length, and also twosemitones. The upper disk has upon it the seven notes or intervals whichare alike in every octave represented by arms or projections, to whichare added the syllables used in singing them-do, re, mi, fa, sol, la,si. The do, which naturally follows in singing, belongs to the nextseries or octave. Do is always the tonic or key-note and when thatsyllable is placed opposite C on the outer disk, all the other syllableswill be opposite a letter on that disk; but when do7 is opposite anyother letter, some of the other syllables will not fall on letters,owing to the unequal division of the scale, but will be found oppositesome letter sharped or flatted; thus the upper and lower disk will showwhat sharps or flats are produced in every key; for instance, if do 1 isopposite D, a syllable will be opposite F#- and Cit; therefore in thekey of D, there are two Sharps. So when do is opposite F, one syllablefalls on Bb; therefore in the key of F there is one flat.

I now proceed to show the uses of the ring in connect-ion with the lowerdisk. No keyed instrument, like the piano, can be in perfect tune,because the intervals are not of the same length, as represented by thedivisions used above. If we divide the lower disk and the ring each intosixty degrees or equal parts, we shall get not the true notes, but avery near approximation; and thatnumber of parts being on a common clockface, it will not be difficult to use these divisions, which I shallcall commas, although they are a little less than a true comma, as itwould berepresented by distance on a circle. In the first scale used, Iassumed that the interval between each tone was of the same length, andit was twice that of the semitone; but the first two intervals vary by acomma: from C to D is l0 commas; but from D to E is only 9; thereforethe truer E would be fixed at one comma lower than in the first scaledescribed; but the diatonic interval, called a semitone, is to berepresented by six commas, which brings the F in both divisions on thesame point. In this scale also the truer A and B are found one commabelow that in the first named scale. The do and other syllable sung areinscribed on the ring in their true places, according to this division,and on turning the ring so as to have the syllable do fall on any letteror division, except C, it will be seen at what points on the fixed scalethe remaining syllables should fall. The ring be required.

bears the same relation to the division into sixty parts on the lowerdisk, which the upper disk bears to the division into twelve parts alsoon the lower disk. The arms within the ring, which support it in itsaxis, show the divisions made in the scale by the common chords, andpoint out the chord of the third and the fifth in any key whatever onthe fixed scale: so other chords may be represented on the moving ringor moving disk.

A truer division of the scale or circle would be into 53 equal partswhen the interval of a major tone would be represented by 9; a minortone by 8, and a diatonic semitone by 5 commas, which division of thescale I claim to use when making the instrument for the use of the morescientific musician.

The divisions on the upper disk and ring may be all represented on onedisk, which may be without the projection on that I now use, bysubstituting marks which would be equally distinct, and illustrative:all the flats and Sharps in their true places on the scale of minutestdivision may also be represented. Lines drawn from the center of themoving disk, like radii may be so arranged as to represent the chords ofthe third and fifth also any others which may The tonometer illustratesequally well the intervals in any minor key for when do is the tonic inthe major key, la is the tonic in the relative minor key, in which lastke the ear sometimes requires the syllables fa and sol to be raised asemitone higher than represented; for instance in the key of A-minor, lafalls on A and fa on F# and sol on G# in ascendin the scale, but indescending fa and sol fall on F and G respectively.

My simple rule for finding the notes of the diatonic scale in any majorkey is: When the tonic is on an even number, the next two notes are oneven and the rest on odd numbers. Vhen the tonic is on an odd numbervice versa. Thus in the key of C, 1Q, 2, 4, 5, 7, 9, 11. In the key ofG, 7, 9, 11, 12, 2, 4,6.

Vhat I claim as my invent-ion, and for which I ask to secure LettersPatent, is'- The employment of a fixed disk, in which the musicalintervals within the octave are represented by divisions of a circle,and the letters commonly used to designate the notes of the fixed scale,in combination with one o1' more arms, disks or rings, rotating aroundthe center of the circle of the fixed disk; on which rotating arms,disksor rings, are the true and tempered divisions of the diatonic scale, soarranged that the relations of these divisions of the diatonic scale,with those on the fixed scale may be clearly seen when the pointdesignating the tonic or key note on the moving scale is placed oppositeany of the divisions of the fixed scale, substantially in the manner andfor the purposes as hereinabove set forth.

SAMUEL D. TILLMAN.

Witnesses:

I. H. UNDERHILL, E. T. TYLER.

